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Relational Algebra
Why Learn Relational Algebra?
In order to find trends and understand the world we live in, people can compare different sets of data. By finding relationships between differing data, we can find invisible trends in the universe.
Venn Diagram
Pizza
People
Restaraunt
Relational Algebra Is the Formal language That runs behind SQL.
Selection
Ďƒ Selects Column
Projection
Ď€ Selects Rows
Cross Product
X Combine Two Relations
Set Difference
−
Elements in One Category but aren't in another category.
Set Difference Example
Set Difference Example
Union Operator
âˆŞ
Element in Both Sets.
Union Operator Example
Intersect Operator
∊
Rename Operator Ď a / b(R)